🚀 go-pugleaf

Since a few people have asked about generating S-records, here's mine.
It converts BSD-style a.out format files on standard input to Motorola
S-record format on standard output.  It has been used successfully with
a 68K emulator and an IDT ROM monitor.

Pat Wood
Pipeline Associates, Inc.
--------------------------------------------

#include <stdio.h>
#include "a.out.h"

#define RECLEN 28

unsigned char buf[RECLEN * 2];

main () {
	unsigned int addr;
	unsigned int entry, size;
	struct exec header;
	register unsigned char *ptr;
	register int num;
	register int checksum;

	read (0, &header, sizeof (header));
	swaphead (&header);

	if (N_BADMAG (header)) {
		fprintf (stderr, "bad magic %o\n", header.a_magic);
		exit (1);
	}

	size = header.a_text + header.a_data;
	entry = header.a_entry;

	lseek (0, N_TXTOFF (header), 0);

	printf ("S0030000FC\n");
	addr = entry;
	while (size > 0) {
		num = size > RECLEN ? RECLEN : size;
		size -= num;
		read (0, buf, num);
		if (addr < 0xFFFF) {
			/* S1 record */
			printf ("S1%02X%04X", num + 3, addr);
			checksum = num + 3 + (addr >> 8) + (addr & 0xFF);
		}
		else if (addr < 0xFFFFFF) {
			/* S2 record */
			printf ("S2%02X%06X", num + 4, addr);
			checksum = num + 4 + (addr >> 16) + ((addr >> 8) & 0xFF) +
				   (addr & 0xFF);
		}
		else {
			/* S3 record */
			printf ("S3%02X%08X", num + 5, addr);
			checksum = num + 5 + (addr >> 24) + ((addr >> 16) & 0xFF) +
				((addr >> 8) & 0xFF) + (addr & 0xFF);
		}
		addr += num;
		for (ptr = buf; num--;) {
			puthex (*ptr);
			checksum += *ptr++;
		}
		printf ("%02X\n", ~checksum & 0xFF);
	}
	checksum = ~(3 + (entry >> 8) + (entry & 0xFF)) & 0xFF;
	printf ("S903%04X%02X\n", entry, checksum);
	exit (0);
}

static char *hexchars = "0123456789ABCDEF";

puthex (x)
int x;
{

	putchar (hexchars[x >> 4]);
	putchar (hexchars[x & 0xF]);
}